(1) Field of the Invention
The present invention relates to an engine overrun preventing system for use in a track-laying vehicle such as a bulldozer, hydraulic excavator or crane, and particularly to an engine overrun preventing system suitable for use in a bulldozer.
(2) Description of the Prior Art
When a bulldozer rolls down a slope, for example, running of the bulldozer is accelerated by its own weight etc., so that the engine is reversely driven, overrunning at a revolution speed beyond the allowable range specified in its specification.
In prior art, if the engine is left in such an overrunning condition, it may cause an engine failure or damage to the engine. In order to prevent the overrun of the engine, the operator has to check and judge on each occasion whether the engine is in the overrun condition and operate a brake or other means to reduce the revolution speed of the engine.